Low Cost Macronutrients in the Micropropagation of Selected Sweet Potato [Ipomoea Batatas (L.) Lam] Varieties
Johnstone M. Mvuria, Omwoyo Ombori

Abstract
Sweet potato is a dicotyledonous plant in the family convolvulaceae family. Although in vitro regeneration protocols have been developed for producing disease and pest free planting materials that can be produced throughout the year, micropropagation cost are high. The objective of this study was to assess in vitro regeneration response of KSP 36 and KEMB 36 varieties using low cost macronutrients source to reduce the cost of micro-propagule production. Three conventional macronutrients; ammonium nitrate, potassium nitrate and magnesium sulphate were substituted each at a time with ammonium fertilizer, potassium fertilizer and Epsom salt respectively. Nodal cuttings were used as source of explants. Results obtained from the present investigation indicated that explants cultured in low cost macronutrient Epsom substitute media, performed better in regeneration in term of leaves and nodes formed compared to the conventional media, while in other substitute significant differences (p > 0.05) were not detected in varieties tested. Use of locally available macronutrients significantly (p < 0.05) reduced the cost of micropropagation of sweet potato. KEMB 36 performed better compared to KSP 36 in regeneration response. There is therefore a potential for using locally available low cost macronutrients source as alternative to the conventional costly laboratory macronutrients.

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